from AM for almost 20 years. Prosthetics and implants customized and tailored for specific patients are already being manufactured by AM. Many developments on the fabrication of soft tissues, for the realization of the fabrication of organs as well as a host of other personalized medical items and sensors, are underway. It has been proved that the use of precise AM replicas would reduce surgery time significantly for many patients.
Alongside the obvious benefits to industry and medicine, AM is explored as a potential aid to humanitarian issues. Intensive research is already taking place in 3D printed food and 3D printed houses to assist in the provision of food and homes/shelters in areas of humanitarian need.
Developing countries can benefit significantly from AM. In general, AM narrows the path for less developed economies to industrialize [13].
1.4 Market Size: Current and Future Estimation
AM market was around US$11 billion in 2019. The worldwide market for AM hardware, software, materials, and services is anticipated to exceed $40 billion by 2027. The industry is expected to grow at a compound annual growth rate (CAGR) of 26.4% between 2020 and 2024 [14]. Figure 1.10 shows the total AM market size under each category from 2014 to 2027. It should be noted that the aforementioned market analysis does not count for the potential adverse effect of 2020 pandemic.
Metal AM is one the fastest growing segment in the world. As shown in Figure 1.11, metal AM is one of the fastest growing sectors of the AM industry. The market size for metal AM was around US$2.4 billion in 2019 including system, material, and service sales. A 27.9% growth in the global revenue from 2019 to 2024 is estimated by the supplier side [15]. Customers, however, expect a weaker yearly growth that results in a total market size of US$7.0 billion in 2024. In fact, the annual growth in the revenue of metal AM materials has been higher than that of photopolymers, polymer powders, and filaments between 2013 and 2018 [4]. The systems that were dominant in the market of metal AM include powder bed fusions (mainly with the laser heat source) and powder‐fed laser directed energy deposition as well as new technologies such as binder jetting and cold spray used for AM. Most material sales include metal powders and wire feedstock.
Figure 1.10 Total AM market size by segment that includes all technologies (metals and plastics) from 2014 to 2027 as forecasted by SmarTech Publishing.
Source: Open access and Reproduced from [14].
Figure 1.11 Metal AM market size in AMPower Report.
Source: Redrawn and adapted from [15].
In terms of market share, the aerospace industry covers the largest share, followed by the medical sector [15]. The aerospace industry profits from the turbine, helicopters, and jet‐engine components fabrication as well as new space applications such as rocket engines, attracting large venture capital worldwide, especially in the United States.
1.5 Applications of Metal AM
AM is on the path to offer disruptive solutions for mass customization, digital fabrication, and decentralized manufacturing as required by the current industrial revolution as a technology for rapid production of prototypes and evolving to reliable techniques for fabrication of customized, low‐volume parts we are in known as Industry 4.0. Machine developers are trying to achieve this goal by improving process throughput, build volume, process control, and available raw materials. As more and more original equipment manufacturers (OEMs) and service enterprises start to adopt AM, this transition speeds up. Due to this active progress in the AM industry, the following statement is well received as it reads, “AM is a disruptive technology that is disrupting itself regularly.”
Figure 1.12 Timeline for adopted, emerging, and future applications of AM.
In general, AM processes started to adapt to different sectors as early as 1990. Figure 1.12 shows this timeline and applications that have embraced AM technology.
As mentioned at the beginning of this chapter, among AM processes, three classes of PBF, DED, and BJ, are integrated into mainstream metal manufacturing widely. PBF can include laser‐ and electron‐beam‐based processes where the heat source for DED can be laser, electron, arc, and plasma. The material delivery system in DED can be either powder‐fed or wire‐fed. As per the applications, these AM classes can be used in various applications depending on the size, complexity, and resolution of components. Figure 1.13 schematically shows these processes' applications based on the component size and accuracy/complexity associated with the component. As seen, for large‐size components, the powder‐fed and wire‐fed DED processes are the most applicable processes, where the printed part may not require high resolution with complex features. In contrast, PBF and BJ can be used for smaller metal parts with higher resolution and complexity. In contracts, it has to be noted that the density of parts produced by DED is almost perfect when in BJ, the density cannot be high. PBF is a middle process that can produce relatively large parts up to 50 cm with high resolution and high complexity using the current state of PBF technology in 2020.
Metal AM has a track record of providing innovative solutions leading to reduced lead time, faster design‐to‐market cycles, or production of previously impossible parts in many industrial sectors. Chief among them are medical, dental, aerospace, defense, energy, resources, and automotive industries. In the following, we will touch based upon the status of metal AM applications in different industrial sectors and review some of the state‐of‐the‐art applications of metal AM in each industry.
Figure 1.13 Most important metal AM processes versus part size, complexity, and resolution needed.
1.5.1 Medical and Dental
The medical industry was one of the early adopters of AM for the fabrication of not only metal parts, but also ceramics, polymers, and FGMs. Metal AM has been used to produce medical devices and tools, surgery guides and prototypes, implants, prosthetics, orthotics, dental implants, crowns, and bridges from biocompatible metals such as various titanium, tantalum, and nickel alloys. These are among the main families of metal AM materials with a somewhat well‐established process‐property record that can be leveraged by companies, clinics, and hospitals that will use AM in the future. The design freedom in the production of complex parts with internal pores and cavities facilitating the growth of cells and the production of patient‐specific parts based on
